A drive system has a low voltage system, a high voltage system, and a transformer. The high voltage system has drive units which correspond to power switching elements. A capacitance in the high voltage system serves as a flouting power source which supplies electric power to each of the drive units. An output voltage of a secondary side coil of the transformer is supplied to the capacitance. A comparator compares the output voltage at the secondary side coil of the transformer with a threshold value. A switching speed change part changes the switching speed of each of the power switching element based on the comparison result of the comparator.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A drive system that changes a switching speed of each of a plurality of power switching elements, comprising: operation means for controlling an operational voltage of a primary coil of a transformer in order to change an output voltage of a secondary coil of the transformer; drive units configured to receive the output voltage of the secondary coil of the transformer as a voltage of a power source and to supply a voltage to power switching elements of a voltage control type; and change means for changing a switching speed of the power switching elements on the basis of the output voltage of the secondary coil of the transformer, using at least one selected from: (a) a resistance value of an electrical path through which the voltage is supplied to a conductive control terminal of each of the power switching elements; and (b) a capacitance between an output terminal and the conductive control terminal of each of the power switching elements.
2. The drive system according to claim 1 , further comprising voltage control means for receiving, as a voltage of a power source, the output voltage of the secondary coil of the transformer, the voltage control means changing the output voltage of the secondary coil of the transformer to a predetermined voltage value, and outputting the changed voltage as an output voltage, wherein the drive units supply the output voltage of the voltage control means to the power switching elements of a voltage control type in order to drive the power switching elements.
3. The drive system according to claim 2 , wherein the voltage control means decreases the output voltage of the secondary coil of the transformer, and the operation means decreases the output voltage of the secondary coil of the transformer when it is estimated that the temperature of the power switching elements becomes high.
4. The drive system according to claim 1 , wherein the operation means controls the operational voltage of the primary coil of the transformer in order to change the output voltage of the secondary coil of the transformer on the basis of a temperature of the power switching elements.
5. The drive system according to claim 1 , wherein the power switching elements form an inverter which is electrically connected to an electric rotary machine, and the operation means controls the operational voltage of the primary coil of the transformer in order to change the output voltage of secondary coil of the transformer on the basis of an input voltage supplied to the inverter.
6. The drive system according to claim 1 , wherein the operation means changes in analogue form the output voltage of each of secondary side coils of the transformer, and the change means changes in analogue form the switching speed of each of the power switching elements based on the change in analogue form of the output voltage of the secondary side coils of the transformer.
7. The drive system according to claim 1 , wherein the operation means the operation means stepwise changes the output voltage of the secondary coil of the transformer, and the change means stepwise changes the switching speed of each of the power switching elements on the basis of the stepwise-changed output voltage of the secondary coil of the transformer.
8. The drive system according to claim 1 , wherein the operational means changes in analogue form the output voltage of the secondary coil of the transformer, and the change means changes in analogue form the switching speed of each of the power switching elements on the basis of the changed output voltage in analogue form of the secondary coil of the transformer.
9. A drive system for changing a switching speed of each of a plurality of power switching elements, comprising: operation means for controlling an operational voltage of a primary coil of a transformer in order to change an output voltage of a secondary coil of the transformer; voltage control means for receiving as a voltage of a power source, the output voltage of the secondary coil of the transformer, the voltage control means changing the output voltage of the secondary coil of the transformer to a predetermined voltage value, and outputting the changed voltage as an output voltage, drive units configured to supply the output voltage of the voltage control means to the power switching elements of a voltage control type in order to drive the power switching elements; and change means for changing a switching speed of the power switching elements, by changing the output voltage of the voltage control means on the basis of the output voltage of the secondary coil of the transformer.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
June 28, 2010
October 9, 2012
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